How do antibodies work?

Answer 1

Function Since antibodies exist freely in the bloodstream, they are said to be part of the humoral immune system. Circulating antibodies are produced by clonal B cells that specifically respond to only one antigen (an example is a virus capsid protein fragment) . Antibodies contribute to immunity in three main ways: they can prevent pathogens from entering or damaging cells by binding to them; they can stimulate removal of a pathogen by macrophages and other cells by coating the pathogen; and they can trigger direct pathogen destruction by stimulating other immune responses such as the complement pathway. Antibodies that bind to surface antigens on, for example a bacterium, attract the first component of the complement cascade with their Fc region and initiate activation of the "classical" complement system. This results in the killing of bacteria in two ways. First, the binding of the antibody and complement molecules marks the microbe for ingestion by phagocytes in a process called opsonization; these phagocytes are attracted by certain complement molecules generated in the complement cascade. Secondly, some complement system components form a membrane attack complex to assist antibodies to kill the bacterium directly. To combat pathogens that replicate outside cells, antibodies bind to pathogens to link them together, causing them to agglutinate. Since an antibody has at least two paratopes it can bind more than one antigen by binding identical epitopes carried on the surfaces of these antigens. By coating the pathogen, antibodies stimulate effector functions against the pathogen in cells that recognize their Fc region. Those cells which recognize coated pathogens have Fc receptors which, as the name suggests, interacts with the Fc region of IgA, IgG, and IgE antibodies. The engagement of a particular antibody with the Fc receptor on a particular cell triggers an effector function of that cell; phagocytes will phagocytose, mast cells and neutrophils will degranulate, natural killer cells will release cytokines and cytotoxic molecules; that will ultimately result in destruction of the invading microbe. The Fc receptors are isotype-specific, which gives greater flexibility to the immune system, invoking only the appropriate immune mechanisms for distinct pathogens.

Answer 2

Antibodies are Y shaped proteins. The ends of the arms of the Y have sections that are variable and unique with each being able to bind to a different shaped protein in a "lock and key" way. When a virus or bacteria enter the body the antibodies bind to proteins on the surface of them and can help to fight the infection in several different ways.

1) They bind directly to the pathogen and interfere with its ability to interact with other cells including cells of your body.

2) They can aid phagocytic cells, which engulf and digest the pathogen, in recognizing the infection.

3) They can trigger a chemical reaction with other blood proteins that results in holes being punched in the bacterial cell walls and directly destroying the pathogen.

4) They help other cells, such as T cells, which serve to also destroy the pathogen and also to amplify the immune response. (This part is also what causes fevers and much of what makes you feel sick when infected).

Answer 3

Antibodies act against foreign antigens in many ways. In agglutination, several immunoglobulin (antibody) molecules bind two or more microbial cells together, causing them to clump. This process hinders the activity of pathogenic organisms and increases the chances that they will be phagocytized. Antibodies may neutralize toxins produced by pathogens by binding to critical portions of the toxins and preventing them from functioning against the body. Antibodies may bind to virus ligands or bacterial adhesins and prevent the pathogen from attaching to cells of the body. Antibodies also act as opsonins, which are molecules that stimulate phagocytosis. Binding of the antibody to foreign antigens on the surface of cells facilitates the action of natural killer lymphocytes. IgG antibody bound to antigen can become enzymatically active and produce hydrogen peroxide to damage and kill the microbe to which it is bound. IgG and IgM antibodies that have bound antigen can trigger the complement cascade.

Answer 4

Function Since antibodies exist freely in the bloodstream, they are said to be part of the humoral immune system. Circulating antibodies are produced by clonal B cells that specifically respond to only one antigen (an example is a virus capsid protein fragment) . Antibodies contribute to immunity in three main ways: they can prevent pathogens from entering or damaging cells by binding to them; they can stimulate removal of a pathogen by macrophages and other cells by coating the pathogen; and they can trigger direct pathogen destruction by stimulating other immune responses such as the complement pathway. Antibodies that bind to surface antigens on, for example a bacterium, attract the first component of the complement cascade with their Fc region and initiate activation of the "classical" complement system. This results in the killing of bacteria in two ways. First, the binding of the antibody and complement molecules marks the microbe for ingestion by phagocytes in a process called opsonization; these phagocytes are attracted by certain complement molecules generated in the complement cascade. Secondly, some complement system components form a membrane attack complex to assist antibodies to kill the bacterium directly. To combat pathogens that replicate outside cells, antibodies bind to pathogens to link them together, causing them to agglutinate. Since an antibody has at least two paratopes it can bind more than one antigen by binding identical epitopes carried on the surfaces of these antigens. By coating the pathogen, antibodies stimulate effector functions against the pathogen in cells that recognize their Fc region. Those cells which recognize coated pathogens have Fc receptors which, as the name suggests, interacts with the Fc region of IgA, IgG, and IgE antibodies. The engagement of a particular antibody with the Fc receptor on a particular cell triggers an effector function of that cell; phagocytes will phagocytose, mast cells and neutrophils will degranulate, natural killer cells will release cytokines and cytotoxic molecules; that will ultimately result in destruction of the invading microbe. The Fc receptors are isotype-specific, which gives greater flexibility to the immune system, invoking only the appropriate immune mechanisms for distinct pathogens.

Answer 5

Antibodies are cells that help the immune system fight off virus and sometimes bacteria. Vaccines are created from the antibodies of viruses that host them. For example a flu vaccine is made of the antibodies of various flu viruses.

With the exception of the Human Immunodeficiency Virus, or HIV, a typical virus only lasts only a couple of days and give off antibodies for your body to work with its white blood cells to fight infection.

When a person becomes ill even with a mild cold your body immidiatly creates anti bodys from the white blood cells. This anti bodys mould themselvs around the bad bacteria and engulf it. the white blood cells then know that if the same bacteria returns it can be faught off straight away.

Answer 6

antibody is a protein made in response to a specific antigen.

antibody attaches to the antigen and makes it useless.

Answer 7

Antibodies are produced by the body's immune cells that can recognize and bind to markers (antigens) on the outside of specific organisms, in this case the measles virus.